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Citrus trees showing natural tolerance to citrus greening disease host bacteria that produce novel antimicrobials that can be used to fight off the disease, our recent study shows. We found the trees at an organic farm in Clermont, Florida. Citrus greening disease – known more formally as Huanglongbing, or HLB, is caused by the bacterium Candidatus Liberibacter asiaticus. It is spread by an insect called the Asian citrus psyllid. There is no known cure for the disease. We are Florida-based researchers who study sustainable farming practices, a discipline also known as agroecology. Our team has isolated these antimicrobial compounds in the lab and is now working to test them with the goal of producing an effective treatment for HLB. Why it matters HLB has dealt a massive blow to Florida’s iconic citrus industry. Since citrus greening disease was first detected in the state in 2005, Florida citrus production is down by more than 92%. The disease is just one factor....

A container ship rammed into the Francis Scott Key Bridge in Baltimore around 1:30 a.m. on March 26, 2024, causing a portion of the bridge to collapse into Baltimore Harbor. Officials called the event a mass casualty and were searching for people in the waters of the busy port. This event occurred less than a year after a portion of Interstate 95 collapsed in north Philadelphia during a truck fire. That disaster was initially expected to snarl traffic for months, but a temporary six-lane roadway was constructed in 12 days to serve motorists while a permanent overpass was rebuilt. U.S. cities often face similar challenges when routine wear and tear, natural disasters or major accidents damage roads and bridges. Transportation engineer Lee D. Han explains how planners, transit agencies and city governments anticipate and manage these disruptions. How do agencies plan for disruptions like this? Planning is a central mission for state and metropolitan transportation agencies. T...

The story of renewable energy’s rapid rise in Latin America often focuses on Chinese influence, and for good reason. China’s government, banks and companies have propelled the continent’s energy transition, with about 90% of all wind and solar technologies installed there produced by Chinese companies. China’s State Grid now controls over half of Chile’s regulated energy distribution, enough to raise concerns in the Chilean government. China has also become a major investor in Latin America’s critical minerals sector, a treasure trove of lithium, nickel, cobalt and rare earth elements that are crucial for developing electric vehicles, wind turbines and defense technologies. In 2018, the Chinese company Tianqi Lithium purchased a 23% share in one of Chile’s largest lithium producers, Sociedad Química y Minera. More recently, in 2022, Ganfeng Lithium bought a major evaporative lithium project in Argentina for US$962 million. In April...

I’m striding along the steep bank of a raging white-water torrent, and even though the canyon is only about the width of a highway, the river’s flow is greater than that of London’s Thames. The deafening roar and rumble of the cascading water is incredible – a humbling reminder of the raw power of nature. As I round a corner, I am awestruck at a completely surreal sight: A gaping fissure has opened in the riverbed, and it is swallowing the water in a massive whirlpool, sending up huge spumes of spray. This might sound like a computer-generated scene from a blockbuster action movie – but it’s real. Alun Hubbard stands beside a moulin forming in a meltwater stream on the Greenland ice sheet. Courtesy of Alun Hubbard A moulin is forming right in front of me on the Greenland ice sheet. Only this really shouldn’t be happening here – current scientific unders...

For anyone who enjoys nature, summer is a fascinating time to be outside. Animals are on the move: Turtles are nesting, baby birds are testing their wings, snakes are foraging and young mammals are emerging. In central Pennsylvania, where I live, last year’s hatchling painted turtles have overwintered in their nests and emerged looking like tiny helpless snacks for raccoons and ravens. I’ve already rescued a baby killdeer – a shorebird that nests in parking lots – that ran off the road and got stuck in a grate. And I’ve watched an eastern chipmunk prey on a nest of towhee chicks. I moved the killdeer to safety because it had fallen into what we call an “ecological trap.” Humans create these traps when we degrade habitat that looks suitable to animals. For killdeer, parking pads and roofs give off all the vibes of a great nesting site – except for the drains – and they have less natural habitat available these days. But I d...